Re: Null Range in Unconstrasined Array

[Stephen Leake <stephen_leake@stephe-leake.org>]

sjw <simon.j.wright@mac.com> writes:

> On Sep 9, 9:35�am, Stephen Leake <stephen_le...@stephe-leake.org>
> wrote:
>> Adam Beneschan <a...@irvine.com> writes:
>> > To elaborate on this a bit further: Suppose you define a record type
>> > for reading a file with Ada.Direct_IO, that looks something like this:
>>
>> > � type Employee_Data is record
>> > � � � Name � � : String (1 .. 50);
>> > � � � Address1 : String (1 .. 40);
>> > � � � Address2 : String (1 .. 40);
>> > � � � City � � : String (1 .. 30);
>> > � � � State � �: String (1 .. 2);
>> > � � � ...
>> > � end record;
>
>> It _could_ depend on whether there's a pragma Pack, or a
>> representation clause, for the record. In the absence of such, I would
>> expect the compiler to treat these components the same way it treats
>> separate objects. Which means I would expect the bounds to be stored
>> with the object.
>
> After leaving out the ..., GNAT allocates 162 bytes for this record
> (no dope bytes). 

Ok, my expectations are duly updated :).

> Also, if you stream it, it takes just 162 bytes on the stream.

That's not surprising: LRM 13.13.2 says:

    3
    S'Write

         S'Write denotes a procedure with the following specification:

    4/2
              procedure S'Write(
                 Stream : not null access Ada.Streams.Root_Stream_Type'Class;
                 Item : in T)

    5
         S'Write writes the value of Item to Stream.


The value clearly does not include the bounds.

-- 
-- Stephe